Gold recovery from waste leachate solution of central processing units utilizing Mg-Al layered double hydroxide aided reducing agent.

Mg-Al layered double hydroxides (LDH) were synthesized via the co-precipitation technique. The materials are employed with a reducing agent to recover gold from the secondary source. The X-ray fluorescence (XRF) analysis indicated that electronic waste's central processing unit (CPU) components contain the highest quantity of gold. Therefore, we leached the CPU into the solution using aqua regia. The adsorption-desorption test was conducted at pH 3 by adjusting the CPU solution, and the [AuCl4]− ion was exchanged from Mg-Al LDH with hydroxide [OH]− ions. By adding a reducing agent to the desorbed solution, colloidal gold was produced and identified using spectroscopy of ultraviolet-visible (UV-VIS). The layered structure of Mg-Al LDH remained unchanged throughout the experiment, as determined using infrared spectroscopy (IR) and powder X-ray diffraction (XRD). Gold was recovered at 1.476 mmol/L out of 3.859 mmol/L (38.25%) in the colloidal phase. [ABSTRACT FROM AUTHOR]